Characteristics of the Observed Offshore Wave Data by the GPS Buoys

This paper explained characteristics of the observed offshore wave, tsunami and tide data for the half year in 2007, obtained by the two sets of the GPS buoy system installed off the Northern Pacific Coast of Japan by the Ports and Airports Department of the Tohoku Regional Development Bureau of the Ministry of Land, Infrastructure and Transport Japan. Two sets of the GPS buoy successfully observed, wave climate, abnormal high waves, and offshore astronomical tides with little data luck only about 2% of the total observation data. Offshore GPS buoys observed much bigger significant wave heights in both normal and abnormal sea states than the shallower seabed wave gauges, meaning that deep-sea wave observation is necessary in order to obtain offshore wave conditions.